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ca74e92b SN |
1 | /* delayacct.c - per-task delay accounting |
2 | * | |
3 | * Copyright (C) Shailabh Nagar, IBM Corp. 2006 | |
4 | * | |
5 | * This program is free software; you can redistribute it and/or modify | |
6 | * it under the terms of the GNU General Public License as published by | |
7 | * the Free Software Foundation; either version 2 of the License, or | |
8 | * (at your option) any later version. | |
9 | * | |
10 | * This program is distributed in the hope that it would be useful, but | |
11 | * WITHOUT ANY WARRANTY; without even the implied warranty of | |
12 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See | |
13 | * the GNU General Public License for more details. | |
14 | */ | |
15 | ||
16 | #include <linux/sched.h> | |
17 | #include <linux/slab.h> | |
18 | #include <linux/time.h> | |
19 | #include <linux/sysctl.h> | |
20 | #include <linux/delayacct.h> | |
21 | ||
163ecdff | 22 | int delayacct_on __read_mostly = 1; /* Delay accounting turned on/off */ |
ca74e92b SN |
23 | kmem_cache_t *delayacct_cache; |
24 | ||
163ecdff | 25 | static int __init delayacct_setup_disable(char *str) |
ca74e92b | 26 | { |
163ecdff | 27 | delayacct_on = 0; |
ca74e92b SN |
28 | return 1; |
29 | } | |
163ecdff | 30 | __setup("nodelayacct", delayacct_setup_disable); |
ca74e92b SN |
31 | |
32 | void delayacct_init(void) | |
33 | { | |
34 | delayacct_cache = kmem_cache_create("delayacct_cache", | |
35 | sizeof(struct task_delay_info), | |
36 | 0, | |
37 | SLAB_PANIC, | |
38 | NULL, NULL); | |
39 | delayacct_tsk_init(&init_task); | |
40 | } | |
41 | ||
42 | void __delayacct_tsk_init(struct task_struct *tsk) | |
43 | { | |
44 | tsk->delays = kmem_cache_zalloc(delayacct_cache, SLAB_KERNEL); | |
45 | if (tsk->delays) | |
46 | spin_lock_init(&tsk->delays->lock); | |
47 | } | |
48 | ||
ca74e92b SN |
49 | /* |
50 | * Start accounting for a delay statistic using | |
51 | * its starting timestamp (@start) | |
52 | */ | |
53 | ||
54 | static inline void delayacct_start(struct timespec *start) | |
55 | { | |
56 | do_posix_clock_monotonic_gettime(start); | |
57 | } | |
58 | ||
59 | /* | |
60 | * Finish delay accounting for a statistic using | |
61 | * its timestamps (@start, @end), accumalator (@total) and @count | |
62 | */ | |
63 | ||
64 | static void delayacct_end(struct timespec *start, struct timespec *end, | |
65 | u64 *total, u32 *count) | |
66 | { | |
67 | struct timespec ts; | |
68 | s64 ns; | |
69 | ||
70 | do_posix_clock_monotonic_gettime(end); | |
71 | ts = timespec_sub(*end, *start); | |
72 | ns = timespec_to_ns(&ts); | |
73 | if (ns < 0) | |
74 | return; | |
75 | ||
76 | spin_lock(¤t->delays->lock); | |
77 | *total += ns; | |
78 | (*count)++; | |
79 | spin_unlock(¤t->delays->lock); | |
80 | } | |
81 | ||
0ff92245 SN |
82 | void __delayacct_blkio_start(void) |
83 | { | |
84 | delayacct_start(¤t->delays->blkio_start); | |
85 | } | |
86 | ||
87 | void __delayacct_blkio_end(void) | |
88 | { | |
89 | if (current->delays->flags & DELAYACCT_PF_SWAPIN) | |
90 | /* Swapin block I/O */ | |
91 | delayacct_end(¤t->delays->blkio_start, | |
92 | ¤t->delays->blkio_end, | |
93 | ¤t->delays->swapin_delay, | |
94 | ¤t->delays->swapin_count); | |
95 | else /* Other block I/O */ | |
96 | delayacct_end(¤t->delays->blkio_start, | |
97 | ¤t->delays->blkio_end, | |
98 | ¤t->delays->blkio_delay, | |
99 | ¤t->delays->blkio_count); | |
100 | } | |
6f44993f SN |
101 | |
102 | int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk) | |
103 | { | |
104 | s64 tmp; | |
105 | struct timespec ts; | |
106 | unsigned long t1,t2,t3; | |
107 | ||
6f44993f SN |
108 | /* Though tsk->delays accessed later, early exit avoids |
109 | * unnecessary returning of other data | |
110 | */ | |
111 | if (!tsk->delays) | |
112 | goto done; | |
113 | ||
114 | tmp = (s64)d->cpu_run_real_total; | |
115 | cputime_to_timespec(tsk->utime + tsk->stime, &ts); | |
116 | tmp += timespec_to_ns(&ts); | |
117 | d->cpu_run_real_total = (tmp < (s64)d->cpu_run_real_total) ? 0 : tmp; | |
118 | ||
119 | /* | |
120 | * No locking available for sched_info (and too expensive to add one) | |
121 | * Mitigate by taking snapshot of values | |
122 | */ | |
123 | t1 = tsk->sched_info.pcnt; | |
124 | t2 = tsk->sched_info.run_delay; | |
125 | t3 = tsk->sched_info.cpu_time; | |
126 | ||
127 | d->cpu_count += t1; | |
128 | ||
129 | jiffies_to_timespec(t2, &ts); | |
130 | tmp = (s64)d->cpu_delay_total + timespec_to_ns(&ts); | |
131 | d->cpu_delay_total = (tmp < (s64)d->cpu_delay_total) ? 0 : tmp; | |
132 | ||
133 | tmp = (s64)d->cpu_run_virtual_total + (s64)jiffies_to_usecs(t3) * 1000; | |
134 | d->cpu_run_virtual_total = | |
135 | (tmp < (s64)d->cpu_run_virtual_total) ? 0 : tmp; | |
136 | ||
137 | /* zero XXX_total, non-zero XXX_count implies XXX stat overflowed */ | |
138 | ||
139 | spin_lock(&tsk->delays->lock); | |
140 | tmp = d->blkio_delay_total + tsk->delays->blkio_delay; | |
141 | d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp; | |
142 | tmp = d->swapin_delay_total + tsk->delays->swapin_delay; | |
143 | d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp; | |
144 | d->blkio_count += tsk->delays->blkio_count; | |
145 | d->swapin_count += tsk->delays->swapin_count; | |
146 | spin_unlock(&tsk->delays->lock); | |
147 | ||
148 | done: | |
6f44993f SN |
149 | return 0; |
150 | } | |
25890454 SN |
151 | |
152 | __u64 __delayacct_blkio_ticks(struct task_struct *tsk) | |
153 | { | |
154 | __u64 ret; | |
155 | ||
156 | spin_lock(&tsk->delays->lock); | |
157 | ret = nsec_to_clock_t(tsk->delays->blkio_delay + | |
158 | tsk->delays->swapin_delay); | |
159 | spin_unlock(&tsk->delays->lock); | |
160 | return ret; | |
161 | } | |
162 |